Dipper tooth construction



July 15, 195 F. E. SMITH DIPPER TOOTH CONSTRUCTION 2 sriEEws -snEETllFiled Feb. 5. 1948 Inventor Forrest Smith y 15, 1952 F. SMITH 2,603,009

DIPPER TOOTH CONSTRUCTION Filed Feb. 5, 1948 v 2 SHEETS-SHEET 2 H I hInventor 1| fbr'rest E Smith Patented July 15, 1952 Yumrso STAT OFFICE2,603,009 nrrrnn roorn oonsrnno'rion Forrest E. Smith, Signal Mountain,Tenn.

Application February s, 1948, Serial No. 5,913

'7 Claims. (01. 37--142) the earth or material being excavated orloaded.

It is desirable that these teeth have sharp cutting edges to facilitateforcing them into the material beingdllg or loaded. It has beenestablished that sharp teeth not only require less force but enable thedigging time per ton to be substantially reduced with decreased wear andtear on the excavator. Unfortunately, in digging in rocky soil orinexcavating certain types of ores, the teeth become blunted very quicklyandmust be frequently replaced. While it ispossible to send the teeth tothe shop to have the lost metal replaced bywelding and thepoint-reshaped, such practice is not only expensive but requires thateach bucket h ve se r s t s e te i V 7 The most common commercial formof renewable teeth require special pins, keys, bolts or the like forfastening purposes. v In most cases these are damaged or worn in'amanner preventing easyremoval and nearly every time a point is changed anew fastening pin or bolt is required for proper fit. Removal of the oldtip'and installation of the new has been diflicult and timeconsumingparticularly under field conditions. Further, the holes forsuch fastening members cause serious weakening of the tooth base. Inorder to provide adequate strength it has been necessary for thefasteners to be placed far back from the edge making it mandatory to usea large renew: ablepoint comprising a large proportion of theentire'weight of the tooth. V V V As a further drawback in the use ofconventional teeth of the renewable type, it has been difficult toobtain firm seating between thetooth base and-the point fastenedthereto. It has been found that any relative movement between the twop'ortions of the tooth tends to increase as time goes on tending todestroy the interiitting faces on both the point and thebaseandnecessitating eventual replacement of the base portion. In mayinstances it is recognized that the renewable point should be replacedas soon; as it is no longer effective as a utting edge, but due to themounting costs of labor and material and the time which is lost in thereplacementprocess, such replacement has been frequently delayed ata'large cost in the ef iciency of excavator operation. i

Accordingly, itis an object of the present in- Yention' to provide arenewable dipper tooth which is not dependent upon the use of bolts,pins, keys or other fastening members with their attendant shortcomings,but which includes a fastener of novel construction serving to keep thetooth parts positively assembled and protected against wear andbreakage. I

t is another object to provide a renewable point for a'bucket toothwhich is small-in size as compared to the base portion thereof so as toreduce the cost and, consequently, justify frequent replacement thereofafter moderate wear in. the.

interest of obtaining maximum operating elfi-- ciency.

It is a further object to provide a renewable bucket tooth which mayreadily be installed or removed in the field with a minimum amount oflabor and a minimum of shut-down time for the machine. l'

It is a furter object of the invention to provide a renewable toothpoint in which the fastening means is integrally formed and soconstructed as not only to enable firm initial seating but also toprevent gradual loosening and the development of play as a result ofprolonged heavy duty serv ice. The renewable point disclosed hereinbecomes even more tightly engaged with the base portion as an incidentto use but may nevertheless be removed very readily with the use of achisel or other simple tool.

Other objects and advantages of the invention will become apparent asthe discussion proceeds taken in connection with the accome panyingdrawings, in which: Figure 1 is a fragmentary view ofth'e lip portion ofa bucketfshowing a series of bucket teeth-alined thereon- Fig. 2 showsthe tip portion of one of the teethof Fig. 1 in a section taken parallelto the bucket axis. 5

Fig. 3 is a fragmentary view showing the tooth disclosed in Fig. 2 priorto the bending of one of the fastening lugs. I Fig. 4'shows thenon-renewable or base portion of a tooth and in particular the fasteningrecesses formed therein. r Y Fig. '5 is .a sectional view of therenewable point taken along line 55 of Fig.2. 0 Fig. 6 shows insertionof a purposes.

tool for removal Fig. 7 shows a -modification of the present inventionin vertical section similar to Fig- 2.

Fig. 8 is a face view of the tooth point of Fig. 8a is a section takenalong line W lla. in

Fig. 9 is a fragmentary view of the fastener portion of Fig. 7 prior tobending one of the lugs into its recess.

While the invention is susceptible of various modifications andalternative constructions and uses, I have shown in the drawings andwill herein describe in detail only the preferred embodiments of theinvention. It is to be understood, however, that I do not intend tolimit the invention by such disclosure, but aim to cover allmodifications and alternative constructions and uses falling within thespirit and scope of the invention as expressed in the appended claims.

Referring now to Figure 1 the invention will be seen applied to anexcavator bucket I having a row of bucket teeth II spaced along thefront edge or lip thereof. Each of the teeth has a relatively massivebase portion I2 and a tip portion or point It renewably mounted thereonand presenting a relatively sharp leading edge II.

In' order to show the details of construction ofthe renewable point andthe means for fastening the same, reference is next made to thetransverse sectional view of Fig. 2 where it will be seen that the baseportion I2 has a tongue I5 re ceived in the point I4. Each side of thebase portion I2 has a recess IS formed therein defining a recessedabutment I8. The front end of the base portion is tapered or charnferedas at IS, the latter portion necking down at a ledge to the tongue i5which is of lesser cross section. As a more detailed structural feature,the recess I6 has a forward or alining portion IBa the purpose of whichwill become apparent as the discussion proceeds. I I

To hold the point I4 firmly seated on the base portion I2, the point isprovided with "a lug 2| on the front and back sides thereof which isadapted tobe deformed into the recess IS in the base portion and to bein clamping engagement with the abutment I8. In the practice of theinvention the lug 2I has a head portion 22 joined integrally with thepoint I4 by a neck 24. The lug 2 I is thus of flaring cross sectionproviding a gripping surface on the underside thereof and'a face portion26 facing outwardly of the tooth. The gripping surface 25 is curved orshaped to conform generally to the shape of the abutment ['8 although,as will be noted in Fig. 2, the parts aresha'ped relatively to oneanother 'so that interference with the abutment I8 takes place first atthe lip portion 25a of the surface 25 as the lug'2l is pounded into theseated position. By reason of such construction only'slight inwarddeformation of the lug 21 is required to cause wedging engagement at thesurface 25a, tending to force the point I4 into intimate jammedengagement with the base portion [2 of the tooth. It will be apparentthat as the lug 2| is forced more deeply into the recess I6, the wedgingor pinching force on the point is progressively increased. 7 v

As shown in the drawing, the head portion 22 ofthe lug is relativelygreat in cross section as compared to the neck 24. Bending thus takesplace almost entirely at the neck since'thisi's the point at which thetorque, due to pounding on the surface 26 for exam'ple, is a maximum."In effect, therefore, the lug is a lever of the second class, causingthe force applied at 25 to be greatly in excess of the force required toproduce inward deformation of the lug.

In order to further insure that bending takes place at the neck 24, Iprovide an internal boss 28 immediatelyadjacent thereto. This boss isformed to be received in the portion Ilia of the 4 recess I6 and to seatfirmly on the root thereof. The boss 28 thus serves as a rigidlyreinforced base to concentrate the bending forces slightly ahead of theregion 25a. As a further detail of construction, it will be noted thatthe parts are proportioned so that a gap 29 exists at the end of theboss 28 so that interference cannot take place at this point. Similarly,a skirt 30 is formed on the point I4 which is separated from the ledge20 by a space 3|. As a result, substantially all of the force exertedbetween the gripping surface 25 and the abutment I8 is effective towedge the point onto the tapered surfaces on the tongue I5 withoutbottoming taking place in any part of the interfitting structure.

In practicing the present invention, the wedgeshaped lug 2I is so formedthat the base portion 26 projects above the surrounding surface to forma projecting hump even when the lug is fully received in its recess. Asshown in Fig. 2 such projection or hump is wedge-shaped, extendingupwardly away from the base of the tooth proper in a direction away fromthe cutting point I'I. Each bite of the tooth thus tends to furthercoinpress the lug 2! due to the crowding of the earth or other materialagainst the face 25. As a; re-

sult, any tendencyof the tip I4 to loosen or develop play as an incident'to use of the shovel is immediately counteracted by the pressure of thematerial being dug. Stated another way. any force on the tooth tendingto cause play to develop, of itself, causes the tooth to be more firmlyunited and therefore to maintain its unitary nature until the edge I! isWorn sumcienuy to require replacement, v

The invention is also concerned with rmovlii of the point after it hasbecome worn. without the necessity of unscrewing bolts or removingrivets or pin-type fasteners. It is proposed instead that a tool channelbe formed in the base portion of the tooth to cooperate with the underportion of the lug to enable the lug to be bent outwardly away from thetooth body, just the 112- verse of th assembling operation. In thepresent embodiment as disclosed in Fig. 2 this is accom*- plished byproviding an access space 34 between the forward facing wall of therecess It and the lug 2I thereby enabling a chisel 33 or similar tool tobe inserted. As disclosed in detail in Flgfi, merely inserting thechisel and pounding the same toward the root of the space 34 issuflicient to wedge the lug 2| upwardly. If desired, the chisel may beemployed as a lever pivoting about the region 35. Because of therelatively short spacing between the pivot area 35 and thepresented edgeof the lug 2|, it is manifest that substantial leverage may be obtained.

In accordance with one of the more detailed aspects of the invention thelug 2| is undercut along its trailing internal edge to provide-a groove36. The latter not only increases the width of the space 34 but enablesa larger and stronger tool to be inserted. Due to theinwardly'extendjing part of the groove 36, the abutment It the baseportionof the tooth is effectively'sliielded against nicking-or otherdamage fromaninsei' ted chisel. Such groove'36 hasalso-been found to beof considerable help in prying the lug upwardly using the region 3'5-asa fulcrum, since it forms'a firm and substantial seat for any insertedtool.

Turning attention now to Figs. 7,, 8 and-'9 another modification of theinvention is shown, be=

ing different from that previously disclosed mi embodiment the baseportion of-tiie tooth car ries a point M. The "latter is telescoped overa tapering tonguebl on the baseportion. 'Ihe point is alug of generallyT-shap'e'having laterally extending tabs 41. On its underside the lughasv a gripping l face 46' which is curved to register generally with anabutting surface ll inthebase portion of the tooth." Just as in theprevious embodiment, the lug45-is general1y= wedge-shaped, having a neckportion 49 at which most of the bending takes'place. Thus; the" headportion of the lug remains substantially unde-' formed as it is poundedinto its seated position.

With the point 4| fully seated, substantially all of the engaging forceis borne by the forwardly tapering surfaces of the tongue 42 Sufficientclearance is maintained at the regions 58, 5| and 52 so that bottomingof the point on the base portion cannot occur.

In accordance with one of the more detailed aspects of the invention,the arms of the T-shaped recess 44 are laterally extended beyond'thetabs 41 on the; lug 45. As will'be more clearly, seen by reference toFig-8, this provides an access space 54. Upon inserting a chisel orsimilar tool in the space 54, the lug 55 may be wedged or pried upwardlyaway from the base portion of the tooth in much the same manner as inthe embodiment previously discussed. If desired, the base portion of thetooth may have a hole 55 centrally formed therein to provide clearancefor both the underside of the lug and for any inserted I tool.

It will be seen that in both of the embodiments the lug is relativelymassive and that the point of bending is coordinated in a veryefficacious manner with an abutting surface on the base portion of thetooth. In all of the embodiments increased deformation of the lugproduces a pinching or wedging effect, causing the tip portion of thetooth to seat more firmly on the base portion. Further, the engagementis not adversely aifected by severe usage but, on the contrary, isincreased to a degree which varies proportion ately with the resistanceand the density of the material being excavated, employing the crowdingaction of the earth. Removal in the field in spite of such firmengagement is readily accomplished Without heavy duty tools or tools ofspecial design.

A solid and durable construction is achieved which at the same timeenables the replaceable dipper point to be made extremely small relativeto the base portion of the tooth. Thus, there is little loss indiscarding a point after the cutting edge has become considerably wornand it is no longer necessary, as a matter of economy, to attemptrebuilding the edge portion by welding or brazing. Furthermore, due toits small size, the point may be formed of the newly developed morecostly alloys without seriously increasing the amount of the investmentper shovel.

While the invention has been described in connection with a tooth for anexcavating bucket, it will be apparent that the teachings in theirbroader aspects are equally applicable not only to other types ofearth-engaging apparatus, but also to other types of tools utilizingrenewable points which must be replaced from time to time because ofwear.

I claim as my invention:

1. A composite bucket tooth having provision for point renewalcomprising, in combinatiod'a; relatively massive base having a recessformed in. a lateral wall thereof, a-- tapered tongueon-theend of saidbase adjacent said recess, a renewable point having a trailing edge andan internal receptable for the mating reception ofnsaid tongue,

ward into said recess so that increased deformation of the lug isaccompanied by intimate jam ming of said tapered tongue in saidreceptacle.

' 2-. A renewable point for a bucket toothor the like having a recessformed on a lateral surface thereof and in which the recess has forwardand rear walls arranged in shallow v-formationico'mprising, incombination, a body portion, a retaining lug integrally formed onthetrailing edge of. the body portion so as tobe positioned over said:

recess when said point'and said bucket toothare in engagement, said lugbeing relatively massive.

and inflexible but havinga neck portionconnecting'it to the point sothat'upon inwardideformae. tion of the lugbending occurs at the neckportion: causing initial binding engagement between the forward wall ofsaid recess and the region of the lug'adjacent said neck portion, saidlug having a head portion which upon seating of the lug in said recessassumes a position spaced opposite the rear wall thereof for the wedgingadmission of a cold chisel or the like to facilitate renewal of thepoint.

3. A renewable point for a bucket tooth or the like having a recessformed on the side thereof comprising, in combination, a body portion,said body portion being hollowed out to provide a receptacle enablingthe point to be telescoped over said bucket tooth, a retaining lugintegrally formed on the trailing portion of the point so as to bepositioned over said recess when said point and said bucket tooth are inengagement, said lug being relatively massive and inflexible but havinsaneck portion connecting it to the point, the body portion of said pointhaving formed therein an internal boss reinforcement adjacent said neckportion to insure that application of inward pressure to said lug isaccompanied by localized bending at said neck portion.

4. A renewable point for a bucket tooth or the like having a recessformed in a lateral surface thereof comprising a point body having areceptacle formed therein for mating reception of the tooth, said pointbody having a lug formed at the trailing edge thereof for reception bysaid lateral recess for locking the point on said base portion, said lugbeing of generally wedge-shaped crosssection and of such thickness as topresent an inclined surface which extends above the surrounding surfaceof the point even when the lug is fully seated in said recess so thatsaid lug is forced increasingly into said recess by the crowd'- ingaction of large rocks and the like during the digging operation.

5. A point for a renewable tooth having a tooth base with a recessformed in a lateral surface thereof, comprising, incombination, a pointbody shaped to form a hollow receptacle for reception of the end of thetooth base, a lug formed on'the trailing portion of said point andhaving a flaring cross section to form a neck and a head portion adaptedto be forced down into said recess to lock the point on the base, thehead portion of the lug QiQQQiQQQ 7 being relieved to provide, a bearingsurface spgced from the wall of said rec ss at. a poin mm??? from theneck portion of the lug to facilipa fse insertion or a prying tool fordisengeging sold leg from said recess.

6. A composite bucket tooth havin provision for point renewalcomprising, in combination, a relatively massive base having a conce verecess formed in a lateral wallthereof, a tapered tongue on the end ofsaid base adjacent said recess, a renewable point having a cutting edgnd on internal receptacle for the mating reception of said tongue, a lugon the trailing edge of said point, having a relatively inflexible bodyand e flexible neck portion, said lug being so shaped as to be reeeivedin said concave recess. said point having an internal reinforcing bossadjacent said neck portion, such boss and the inflexible nature of thelug body serving to coneentraige bending at said neck portion, the wallof said conceive re: cess being so positioned that the lip portionthere: of is engaged vfirst as the lug is pounded down.- wardly intosaid recess whereby said tapered tongue is jammed intimately into saidre ptacl 7 A composite bucket tooth having provision for point renewalcomprising, in combination, a relatively massive base having a, concaverecess 8 min d in a lat ra W111 th reof, a t erin nsi on we on 9i s le apbi i ki it a d r cess and o ing; longibiidinel groove'fiherein'; 'gnewable mini evee" We g ed e a an nte nelr c esle $0 irs e e i n 9! aid@neueiel'us i jl eireile' e's of s i poi t a d nosi i n d ov r sai r cesa i' 1 8 be n 15. some e8 be'm vea l' f 'e on nwa d de er e ny T p d ine el l -i on ii slinelly axree's ei l ib 'i' nfi aid ue..-.sa bo e e lirserving t6 e ag h oove i v lid P e s: j eem etp q e i u s se vin as rgimens? q dimmed? bending o said .8 i s $5 9 1 i nn' c ooes; he illsismunded dqwewe d 'v 1 th s id itec FQEEEST'E- MITHJ eereeems (RI-TEDTile following references are of record in one file of this patent:

UNITED STATES Pereme 2392s? sews J'ee- 5 1943

